ts431-z adjustable precision shunt regulator 1/10 version: c14 sot - 23 general description ts431 integrated circuits are three-terminal progra mmable shunt regulator diodes. these monolithic ic voltage references operate as a low temperature coefficient zener which is programmable from v ref to 36 volts with two external resistors. these devices exhibit a wide op erating current range to 250 ma with a typical dynamic impedance of 0.2 w . the characteristics of these references make them excellent replacements for zener diodes in many applications such as digital voltmeters, power supplies, and op amp circuitry. the 2.495v referen ce makes it convenient to obtain a stable reference from 5.0v l ogic supplies, and since the ts431 operates as a sh unt regulator, it can be used as either a positive or n egative stage reference . features programmable output voltage up to 36v ts431a C v ref 2.495v 1% tolerance ts431b C v ref 2.495v 0.5% tolerance fast turn-on response sink current capability: 200ma low dynamic output impedance: 0.2 ? (typ) min. operating cathode current: 0.2ma (typ) halogen free ordering information part no. package packing ts431acx-z rfg sot-23 3kpcs / 7 reel ts431arcx-z rfg sot-23 3kpcs / 7 reel ts431bcx-z rfg sot-23 3kpcs / 7 reel note: g denotes for halogen- and antimony-free as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total br + cl) and <1000ppm antimony compounds block diagram absolute maximum ratings (t a = 25 o c unless otherwise noted) parameter symbol limit unit cathode voltage v ka 36 v continuous cathode current range i k +250 ma reference input current range i ref 10 ma power dissipation p d 0.25 w operating temperature range t oper -20 ~ +85 o c junction temperature t j -40 ~ +125 o c storage temperature range t stg -40 ~ +125 o c thermal resistance junction to ambient r ? ja 156 o c/w note: r ? ja is measured with the pcb copper area of approximat ely 1 in 2 (multi-layer) ts431 - z pin definition: 1. reference 2. cathode 3. anode ts431 a r - z pin definition: 1. cathode 2. reference 3. anode
ts431-z adjustable precision shunt regulator 2/10 version: c14 electrical characteristics (t a =25 o c, unless otherwise specified) parameter symbol test conditions min typ max unit reference voltage ts431a v ref v ka =v ref , i k =10ma (figure 1) 2.470 2.495 2.520 v ts431b 2.483 2.507 deviation of reference input voltage ? v ref v ka = v ref , i k =10ma (figure 1) t a =-20~85 o c -- 6 20 mv radio of change in vref to change in cathode voltage ? v ref / ? v ka i ka =10ma, (figure 2) v ka = 10v to v ref -- -1.2 -2.0 mv/v v ka = 36v to 10v -- -1.0 -2.0 reference input current i ref r1=10k ? , r2= , i ka =10ma (figure 2) -- 1.5 3.5 a deviation of reference input current, over temp. ? i ref r1=10k ? , r2= , i ka =10ma t a =-20~85 o c (figure 2) -- 0.4 1.2 a off-state cathode current i ka (off) v ref =0v (figure 3), v ka =36v -- 0.1 1.0 a dynamic output impedance | z ka | f<1khz, v ka = v ref (figure 1) -- 0.2 0.5 ? minimum operating cathode current i ka (min) v ka = v ref (figure 1) -- 0.2 0.5 ma * the deviation parameters ? v ref and ? i ref are defined as difference between the maximum valu e and minimum value obtained over the full operating ambient temp erature range that applied. * the average temperature coefficient of the reference input voltage, a v ref is defined as: where: t2-t1 = full temperature change. v ref can be positive or negative depending on whether t he slope is positive or negative. example: maximum v ref =2.496v at 30 o c, minimum v ref =2.492v at 0 o c, v ref =2.495v at 25 o c, ? t=70 o c v ref | = [4mv / 2495mv] * 10 6 / 70 o c 23ppm/ o c because minimum v ref occurs at the lower temperature, the coefficient i s positive. * the dynamic impedance z ka is defined as: | z ka | = ? v ka / ? i ka * when the device operating with two external resis tors, r1 and r2, (refer to figure 2) the total dyna mic impedance of the circuit is given by: | z ka | = ? v / ? i | z ka | * ( 1 + r1 / r2)
ts431-z adjustable precision shunt regulator 3/10 version: c14 test circuits figure 1: v ka = v ref figure 2: v ka > v ref figure 3: off-state current additional information C stability when the ts431a/431b is used as a shunt regulator, there are two options for selection of c l , are recommended for optional stability: a) no load capacitance across the device, decouple a t the load. b) large capacitance across the device, optional dec oupling at the load. the reason for this is that ts431a/431b exhibits inst ability with capacitances in the range of 10nf to 1 uf (approx.) at light cathode current up to 3ma (typ). the device is less stable the lower the cathode voltage has been set f or. therefore while the device will be perfectly stable operating at a cath ode current of 10ma (approx.) with a 0.1uf capacitor across it, it will oscillate transiently during start up as the cathode current passes through the instability region. select a very low capacitance, or alternatively a high capacitance (10uf) will avoid this issue altogether. since the user will probably wish to have local decoupling at the load anyway, the most cost effect ive method is to use no capacitance at all directly across the device. pcb trace/via resistance and inductance prevent the loc al load decoupling from causing the oscillation dur ing the transient start up phase. note: if the ts431a/431b is located right at the load , so the load decoupling capacitor is directly acro ss it, then this capacitor will have to be 1nf or 10uf.
ts431-z adjustable precision shunt regulator 4/10 version: c14 applications examples (continue) figure 4: voltage monitor figure 5: output control for three terminal fixed regulator figure 6: shunt regulator figure 7: high current shunt regulator figure 8: series pass regulator figure 9: constant current source
ts431-z adjustable precision shunt regulator 5/10 version: c14 applications examples (continue) figure 10: triac crowbar figure 11: scr crowbar figure 12: single-supply comparator with temperature-compensated threshold figure 13: constant current sink figure 14: delay timer vin vout vref 0.74v
ts431-z adjustable precision shunt regulator 6/10 version: c14 typical performance characteristics figure 15: small-signal voltage gain and phase shir t vs. frequency figure 16: reference impedance vs. frequency
ts431-z adjustable precision shunt regulator 7/10 version: c14 typical performance characteristics (continu e) figure 17: stability boundary condition figure 18: pulse response
ts431-z adjustable precision shunt regulator 8/10 version: c14 electrical characteristics figure 19: reference voltage vs. temperature figure 20: i ref vs. temperature figure 21: i ka vs. v ka (ua) figure 22: i ka vs. v ka (ma)
ts431-z adjustable precision shunt regulator 9/10 version: c14 sot-23 mechanical drawing unit: millimeters marking diagram rx = device code r1 = ts431a ( 1%) ra = ts431ar ( 1%) r2 = ts431b ( 0.5%) y = year code 2 = 2012, 3 = 2012, 4 = 2014 . w = week code 01 ~ 26 (a~z) 27 ~ 52 (a ~ z) x = internal id code
ts431-z adjustable precision shunt regulator 10/10 version: c14 notice specifications of the products displayed herein are subject to change without notice. tsc or anyone on its behalf, assumes no responsibility or liability for any erro rs or inaccuracies. information contained herein is intended to provide a product description only. no license, express or implied, to any intellectual property rights is granted by this document. except as provided in tscs terms and co nditions of sale for such products, tsc assumes no liability wh atsoever, and disclaims any express or implied warr anty, relating to sale and/or use of tsc products includi ng liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, cop yright, or other intellectual property right. the products shown herein are not designed for use in medical, life-saving, or life-sustaining applica tions. customers using or selling these products for use i n such applications do so at their own risk and agr ee to fully indemnify tsc for any damages resulting from such i mproper use or sale.
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